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Sothius' Home-Museum-AMSTRAD- Schneider Joyce Plus-additional pictures

Schneider Joyce Plus
Additional pictures. Note that loading the page could take a while...
(pictures copyright by M.A.Grundke)

PCW8512 serial number 1 (28 KBytes)
keyboard serial number:
5336342892



PCW8512 serial number 2 (22 KBytes)
system unit (monitor) serial number:
5616332215



PCW8512 system overview (47 KBytes)
Joyce Plus system unit overview:
Because it is integrated in the monitor, the motherboard (right, with expansion- and printer-ports) must be extremely compact. Right from the board are also the two integrated drives. By the way, there has also been a Joyce-prototype with integrated printer. Unfortunately, there were heat-problems and the idea was quickly abandoned



PCW8512 board overview (60 KBytes)
Joyce Plus mainboard overview:
As mentioned earlier, the board's compact and highly integrated (at least for its time). Right, you can spot the 16 pcs. 256Kx1 RAMs (which are NEC D41257C-15, by the way, and located at IC104-IC119). Left above it, the Z80 CPU (IC102, with expansion port behind), and in the middle of the board the AMSTRAD 40028 gate array (IC101). On the board's left side are the I/O-devices (top to bottom): the AMSTRAD 40026 printer controller (IC701, with printer connector behing it), the SED9420CAC (2nd floppy controller, IC201) and the NEC D765AC-2 floppy-controller (IC203). Left below that, the buzzer (S101), and on the board's front the 4 pin powercables for the two diskdrives, as well as the floppy connector (flatbed data cable, which connects to both drives)



PCW8512 board silkscreening part 1 (23 KBytes)
board silkscreening, part 1 (board's lower side):
AMSTRAD
1985
COPYRIGHT
Z70291



PCW8512 board silkscreening part 2 (27 KBytes)
board silkscreening, part 2:
AMSTRAD
1985
COPYRIGHT
Z70291
Above it, the power supply connector



PCW8512 board silkscreening part 3 (17 KBytes)
board silkscreening, part 3:
MC0030B
Above, the Panasonic EFB-RD 'piezo-electric ceramic buzzer' at S101



PCW8512 CPU (39 KBytes)
The PCW8512's Z80A, running at 4 MHz. This CPU makes the machine CP/M-capable, and since the Joyce came with CP/M Plus 3.0 by default, the whole range of CP/M-software was usable (as long as it came on the unusual 3"-disks, or you had an external 5.25"/ 3.5" drive). The Z80 was a very popular 8 bit microprocessor with 16 bit adressing range (i.e. 64K). It was a descendant to Intel's 8080 and fully code compatible, but adding several other useful instructions. Behind it, however, part of the machine's expansion port



PCW8512 RAM bank (47 KBytes)
The Joyce Plus RAM bank, consisting of 16 pcs. NEC D41257C-15 (256Kx1). The original Joyce came with only eight of these for a total of 256 KBytes. Looking at the jumper settings documented below, you can see that also a 128K configuration was planned (but never released...). However, the Joyce could, with 3rd party expansions, be expanded to 2 MBytes RAM



PCW8512 RAM size DIP-switch (23 KBytes)
The Joyce Plus memory-selection DIP switch. Settings are as follows:

SizeType1234
512KB256Kx1OFFONOFFON
256KB256Kx1ONOFFOFFON
128KB64Kx1OFFONONOFF
128KB256Kx1ONOFFONOFF



PCW8512 printer controller (35 KBytes)
The AMSTRAD 40026 controls the Joyce-printerport. Without an additional interface card, only specific printers were usable. Furthermore, the 40026 contains a bootstrap program, which is initiated at power-up and scans the A: drive for a bootable disk (that's also the reason why there's no boot-screen: no dedicated firmware or boot-ROM exists in the Joyce)



PCW8512 gate array (44 KBytes)
40028 is a custom gate-array made by AMSTRAD. It contains a monochrome graphic controller and the machine's keyboard controller. The graphic controller can output either at 60Hz (at 720x200) or 50Hz (at 720x256). Similar to the Hercules Graphics Adaptor (720x348) for early PCs, the high resolution is optimal for the machine's main purpose: word processing



PCW8512 floppy controller (37 KBytes)
The NEC D765AC-2 is a floppy-controller which was also used in early PCs. It is not DMA-capable (at least not in the Joyce architecture) and transfers data with 250 KBits/ second. Two 3" floppy drives are possible in the Joyce, although the D765AC-2 should be able to cope with four



PCW8512 SED9420 (36 KBytes)
Couldn't find information on that 'SED9420Cac' anywhere, but it's a 'data separator'. Since it's connected to the floppy controller via SYNC and DATA/ RDATA-signals, I guess it's needed to transfer data read by the FDC. Also, it wasn't present in the 'original' Joyce-design, which only had the 169 KByte diskdrive - it appeared first with introduction of the the newer 706 KByte drive (so most probably adding CF2DD-capability to the Joyce-design). The SED9420C was also used in later AMSTRADs, such as PC3386SX



Sothius' Home-Museum-AMSTRAD- Schneider Joyce Plus-additional pictures